Field
The present invention relates to a method and apparatus for controlling a message over a heterogeneous network and, more particularly, to a method and apparatus for controlling a message over a heterogeneous network, which simplify a message transmission/reception system between heterogeneous networks having messages of different formats, reduce a message transmission/reception latency time, and maintain a transmission sequence according to a point of time at which a message is generated.
Description of the Related Art
The controller area network (CAN) protocol is a network of a single bus topology form. In the CAN protocol, several nodes are connected to a single bus, and access a medium using a contention method and exchange information. The data of a CAN message delivered over a network includes signals to be transmitted. The signal means a minimum unit having a meaning on a network, such as input/output or control input of a sensor or a driver. Such a signal is transmitted using a message over a CAN network. The message means that it has been reconstructed in a form capable of being uploaded onto a CAN bus by taking into consideration the transmitter and recipient of a signal, the length and transmission cycle of a signal, and the characteristics of time, such as the closing time of a signal.
The CAN is chiefly used to deliver control information, and thus a maximum length of a message that may be transmitted is not so great. However, heterogeneous network protocols, such as Ethernet and MOST, have a greater maximum transmission length than the CAN. There is a need for the fragmentation and reassembly process of a message due to such a difference in the maximum transmission length.
In this case, there is a problem in that a gateway needs to separately manage fragmented messages. Furthermore, there is a problem in that a node that receives fragmented messages needs to separately manage received fragments because it receives a message caught in the middle. There is a problem in that a total transmission time of fragmented messages is delayed due to a message caught in the middle.
Korean Patent No. 10-0583811 relates to “THE CAN MESSAGE IDENTIFIER ALLOCATION METHOD AND THE CAN MESSAGE TRANSFER ARBITRATION METHOD FOR THE HUMANOID ROBOT”. The patent discloses a method for using an extension message form of the CAN 2.0B version, defining a basic ID of 11 bits of an arbitration field as a 3-bit class portion and an 8-bit priority level, and increasing priority of a CAN message eliminated from arbitration if two or more messages are generated in order to obtain a bus when the CAN message is transmitted by decreasing the priority level so that the CAN message has high priority upon next transmission.
Korean Patent No. 10-1351285 relates to “METHOD AND APPARATUS FOR TRANSMISSION OF DATA BETWEEN CAN NETWORK AND ETHERNET NETWORK”. The patent discloses a data transmission method and apparatus includes a gateway configuration initialization step of receiving a connection establishment request from an Ethernet client that attempts to perform CAN-Ethernet communication, receiving a filtering condition on a CAN network element that needs a data exchange with the Ethernet client, and performing gateway configuration initialization, a first message check step of checking whether a CAN network message has been transmitted from a CAN channel, filtering the CAN network message based on the filtering condition according to a CAN ID included in the CAN network message, and storing a first message from which the CAN network message has been filtered in a first message repository set for each CAN ID, and a the first message transmission step of, when the first message is stored in the first message repository, checking the first message, including information stored in the first message and a destination address to identify the Ethernet client in Ethernet data, and transmitting the Ethernet data to an Ethernet channel.